This blog is a lab notebook for my work with the Reprap open source 3D printing undertaking.

Thursday, June 14, 2012

Is Reprap UP! to the Chinese challenge?

It appears that Delta Micro's UP! and UP! Mini are aiming to be a serious threat to Reprap and other personal 3D printer offerings in very short order.

Some months ago, a long term technology friend of mine acquired an UP! While Peggy has been a inspired developer of educational technology for years, she did not, to the best of my knowledge, have any prior knowledge of the ins and outs of 3D printing on personal printers. In spite of that, Peggy whipped her UP! printer out of the box and did a brilliant print first time out. That really caught my attention. I'd been working on the Reprap project for years and still, when I bought a Rapman, a greatly enhanced Darwin-derivative, several years ago it had taken me the better part of a month to get used to the quirks of printing on it to the point that I could get reliably good prints.

The UP! 3D printer by Delta Micro

At the time I had abandoned my effort to build a second generation Darwin-derivative printer as simply taking too much time and getting in the way of other design work I wanted to do. My Rapman, however, was getting a little long in the tooth and, should parts break I would not have the means to print replacements. Clearly, I needed another printer.

I had been idly interested in the UP! for some time. Delta Micro, which makes the UP! is the Chinese equivalent of Stratasys here in the US. Some years ago, I suggested to Stratasys that they leverage the highly sophisticated solids model processing app that they supply with their high-end printers to promote a inexpensive, personal 3D printer in the Reprap price range. To Stratasys' credit, they eventually did introduce such a printer that they marketed though Hewlett Packard. Unfortunately, their price point, which was around $14K, was well beyond the means of most pocketbooks for personal use. Delta Micro, on the other hand, did leverage their high-end solids model processing app to promote their own personal printer, the UP!. The UP! was priced at about $1.5K, roughly the same as my Rapman costs currently.

After much agonizing about abandoning the Sampo printer I'd spent considerable money in developing, I went ahead and purchased an UP!. My notion was to get a close look at it to see how much of what Delta Micro said about it was true and how much was hype.

Out of the box, one thing that immediately struck me was the tiny size of the UP! The 140x140x135mm print volume reminded me a lot of the old Makerbot Cupcake. It took me about half an hour to get out of the box and set up, ready for operation. While the manuals indicated that I might have to level the print surface, this was not necessary. Calibrating the printhead height took about ten minutes. When I ordered the UP, I was very worried about print adhesion to the print surface. Delta Micro offered three solutions; perforated printed circuit board, painted glass and Kaplon tape covered glass. I had had so much drama with prints peeling off of the print table with the Rapman over the years that I ordered all three options.

As it turned out, I need not have bothered. The simplest option, perforated printed circuit board, clipped onto the print table with standard office clips, has proved perfectly adequate.

Printing on perforated printed circuit board

I had been assured by the American distributor that the UP! had a heated print table. It certainly didn't look that way out of the box. The black iron print table is heated by a central heating element in the middle of the table. This arrangement struck me as dubious. The control app that goes with the UP lists the table as heating to 105 degrees C. I was worried about the temperature gradient of the print table and did a bit of thermal imaging.

Thermogram of the bare printer table

Interestingly, the thermal gradient between the center of the table to the edge was only about 5 degrees. When I laid the perforated printed circuit board over the print table, I got about a 10 degree overall drop in the print surface.

Print table with the perforated print circuit board

The addition of the board evened out the print table temperature quite nicely so that there was very little in the way of a gradient from the center of the table to the edges.

Construction of the UP! was quite simple. The enclosure is basically stamped sheet steel. Positioning is done with stepper driven belts and flat plate linear guides with grooved edges. It is very simple and very robust. I found out how robust when I accidentally knocked the UP! off of the stool it was sitting on in the first picture in this article. Horrified, I picked it up and could see no damage. With considerable dread I restarted the printer and discovered that it hadn't even been knocked out of alignment. It had fallen about 80 cm onto a linoleum covered floor. This is not something I'd recommend be made into a regular practice, mind.

While the UP! uses an SD card like the Rapman, it is permanently mounted on the controller board. You load the card via a USB link to your computer and start up the print. After the print is started, the printer no longer needs a USB connection to your PC.

As I mentioned earlier, one of the original attractions of the UP! was that it had leveraged the software app from Delta's high end printers. I was especially struck with the sophistication of the structural support capabilities reflected in this picture.

Teapot printed on the UP! with breakaway structural support

One thing that I noticed about the UP! was that I had far less trouble printing tiny objects than I had with the Rapman. The UP! is a bit different than Reprap machines in that it extrudes ABS at 270 C rather than the usual 235 C that the Rapman allows. The thermal footprint of the 1.7 mm filament extruder is much, much smaller than the extruders that I've had experience with it the past and rather looks like the one that Adrian Bowyer, the father of the Reprap project, designed for the Reprap Huxley machine.

Delta had one picture, since removed from their website showing how you could stack objects on top of each other spaced a centimeter or so and the support capability of the system would print them quite nicely. Frankly, I had severe doubts about the ease with which print rafts and structural support could be removed. Experience with the printer, however, has proved those doubts to have been unjustified.

As an example, I recently printed parts for a hand movement sensor for a haptic telepresence robot on the UP! You can see here a particular print positioned in the print volume.

Finger rings for a hand motion sensor as seen on the UP! solids processing app

Printing the support structure of the rings

Completed print

Support material removed

I was able to recover the printed rings from the support material and clean them as you can see here in less than a minute without hurrying. When Delta says breakaway support material, they aren't joking.

One of the apparent drawbacks of the UP! is the implication that it only uses Delta supplied polymer. At roughly $25/lb, it is a bit pricey for an old Scots-Irishman like myself, so I inquired if using third party filament would void my warranty. I was told that I could use whatever I wanted in the printer, but if I burned out or otherwise damaged the extruder it cost less than $300 to buy new one.

One thing that created a problem is that the UP! uses 1.7 mm filament whereas the standard for Stratasys and an increasing number of Reprap machines is 1.75 mm. Fortunately, I have a good working relationship with Jim Waring at New Image Plastics. I have had good results using his 3 mm filament in the past and was able to get him to extrude several pounds of that polymer in 1.7 mm diameter so that I could try it out with the UP!.

The last exercise with the finger rings was done with New Image filament. There appears to be no substantial difference in print quality between the ABS polymer which he makes, which is manufactured in Taiwan and what Delta supplies with the UP! Jim's filament, however, sells for $9.95/lb rather than $25/lb, a considerable savings.

Finally, it appears that Delta Micro is going for the throat of the manufacturers of Repraps in the US and elsewhere. They are now offering a slightly smaller printer, the UP! Mini! with a 120x120x120 enclosed print volume which uses standard 1.75 mm filament for less than $1,000. The UP! Mini appears to be a serious challenge to both the Reprap variations and to the 3D Systems Cube system. It strikes me that unless the quality and ease of use of UP! competitors makes a rather quick quantum leap they could easily find themselves to be a historical footnote in the history of 3D printing rather than a new paradigm of virally diffused technology.

The Taiwan-supplied polymer that New Image uses these days has little, if any, odor. They shifted to that last year. I have the printer sitting right by my graphics workstation, thanks to the very short USB cable that came with the printer. I haven't really noticed any odor.

interesting review thank you.Particularly interesting as all of my incarnations of an extruder using various sources of 3mm and 1.75 ABS have required an extrude temp of 260-265C for best results on my extruders. I have not taken it to 270C thou..

Yet every one Else seems to manage at 210-240C.

What temperature is the support printed at?

Or is it just printed at high speed making it stretch a lot to spider web thickness?

Good to see some positive info coming up on these printers. I bought one for commercial use 2 years ago and have probably put 100lbs of filament through it. There were a few quirks at the start but I have been extremely happy with it. The build quality seems vastly better than anything I've seen from a 3mm-fed reprap and the ease of use is a real bonus.

The newer models have got quite a few uprated components compared to mine, and most of those have been sent to me free of charge. Anything that has broken was forward replaced, free of charge, no questions asked.

The build platform is aluminium. We have 2 and use spray-can gloss acrylic paint on them for adhesion. Every 5 prints we re-spray the paint and then after 5 coatings or so (as the thickness builds), we scrape it off with the spatula. Probably an average of 10 seconds work per print?

BodgeIt: The support is printed at the same temp and speed as the main filament as near as I can tell. It is just printed as a single strand width and with limited contact to the model to allow it to be removed. Any overhangs are printed onto a raft that sits on the support.

The extruder oozes very slightly during heat-up and occasionally there is some light spider webs of filament, but nothing that has ever affected model quality.

Have just bought a 2nd one of these and wish I'd got the mini as a complementary one.

Oh, one thing we did at the very start was to run the thing in a cardboard box as a sort of basic heated build chamber and draft excluder. That and the acrylic made it possible to print platform sized pieces without warping.

One thing that is worth noting is that the build area is 10mm in each dimension smaller than the platform, due to how it calculates the raft placement. I haven't tried it raftless.

Bodgeit: I can't keep track of the temperature of the extruder to know for certain that they aren't changing it for different conditions during a print.

I also can't say if the extruder reverses to contain ooze. It is very quiet and there is no indication of what might be happening during a print in that regard.

As to the temperature range for extrusion. Notice that the listed temperature for the heated print table is 105 C while I measured ~80 C with my thermogram. We all know that where you put the thermistor in an extruder head has a lot to say about what apparent temperature the extruder is operating at.

What I can do is set up the thermal camera and zero in on the extruder orifice and measure the temperature of the ABS coming out of the orifice. I've done that on the Rapman. There should be no problem getting a 1 pixel wide fix on the filament coming out of the UP! orifice.

I've had an Up! for about six months for hobby use, and consumed around 10kg of plastic so far.

Just a couple of comments to add....

The Up! does retract the filament to minimize oozing.

Many Up! users use third-party ABS, and rely have problems. The main issue is that a lot of 3rd party filament isn't manufactured with any sort of quality control on the diameter; but this will be an issue no matter what printer you own. Out of the box, the printer can handle filament from about 1.65mm to 1.85mm without a problem. Filament manufactured to 1.75mm +/- .05mm (like from Makerbot, Protoparadigm, and other quality suppliers) will work fine.

There are a couple of mods available which make the printer more forgiving of filament diameter. My printer can handle about 1.50mm to 1.95mm, which covers nearly all nominal 1.75mm filament out there (with a couple of exceptions for notably bad filament I've gotten).

Most Up! owners stick to printing ABS. It is possible to print PLA on an Up!, but requires making a number of mods. The filament feed stepper gets quite hot in normal operation, and this softens and jams PLA, so people who successfully print PLA have done a lot of work to control heat around the feed gear.

As you noted, the Up! hardware is simple and robust, and the software does a lot of magic. The software only has a few settings, but prints well in materials from a variety of suppliers. The supports it generates work really well and (usually) break of easily and cleanly. The user interface is relatively straightforward and easy to use.

IMHO, the open source community needs to focus a lot more effort on the software side. I don't think there's any rocket science going on, just decent attention to generating good slicing and support combined with sensible defaults and a straightforward UI.

My experiences with the UP! are not so positive. Its frame would actually bend when you push the build platform in the wrong place and you would get skewed 3D prints. The connectors of the thermocouple also are not so good, about half of the time you need to restart the machine, and move it around a bit before the temperature is measured correctly again. Also, I know of at least one other person who has had two UP!s that both broke and he couldn't repair them, even though he was very technical.

The usability of the software is good, but you are limited to three layer heights (IIRC), and not very detailed ones (as I'm used to from the Ultimaker). I guess it's a fairly good machine if you don't want to invest a little bit of time and get more out of it. There are better alternatives, but of course I could be biased because I'm involved in Ultimaker.

"Its frame would actually bend when you push the build platform in the wrong place and you would get skewed 3D prints."

Wow! That sounds horrible! I haven't noticed either the frame or the thermocouple problem you're talking about. I am wondering if these problems have been addressed in current production? How long ago were the printers you are talking about acquired?

"I guess it's a fairly good machine if you don't want to invest a little bit of time and get more out of it."

I bought it primarily to get a look at the software and agree that the settings options you're given aren't extensive. My current feeling is that their software, limits for settings notwithstanding, is the best out there. This edge is largely due to the breakaway support capability.

I think the UP support works because it effectively builds an elevated raft under the horizontal bits that need supporting. I expect it is a little lower than the normal layer height so the layer built on it only bonds weakly.

Does the layer that is supported have more cylindrical ridges on its underside?

Skeinforge support is just an open scaffold with nothing on the top. And it as the normal layer height. I think that makes the layer extruded onto it sag between the gaps in the support so it forms a weaker bond to the layer above but bonds quite strongly to the support.

@Nop "I think the UP support works because it effectively builds an elevated raft under the horizontal bits that need supporting. I expect it is a little lower than the normal layer height so the layer built on it only bonds weakly."

That seems to be the way it works.

"Does the layer that is supported have more cylindrical ridges on its underside?"

I am not sure what you are saying here.

@Caleb 0.5 mm nozzle. It puts out a print filament of about 0.51 mm as best as I can see. Very little swell.

What I meant was is the filament on the bottom layer not pressed flat like a Reprapped object but still largely cylindrical. That would account for it being easy to break away as it only would only have tangential contact with the raft.

@Nop I'm not quite sure yet. When I see support platforms for raised, horizontal bottom-side surfaces, the support platform looks pretty flat, though not completely. When a support platform for a raised, curved surface is printed the support surface looks a bit knobbly. I'm not sure how they achieve that effect.

It is as you say in the second case, though, contact between the support cradle and the print object tends to be sporadic and tangential.

This technique isn't perfect by any means. I've noticed that it tends to work best with large, gently curved surfaces. Smaller, more tightly curved surfaces don't print all that brilliantly. They print well, mind, just not brilliantly.

I brought my UP! 3 days back and have got some fantastic results. However I am printing one more right now and observe that the support built up at the base is lifting off even as the model is printing.(Did not happen on the previous ones i printed) Not sure if this will affect the overall dimensions.How often does the pad need replacement?

Oops! The lifted plastic base made the whole thing distorted. Printing an object like a rectangular block roughly 80mm wide X 30mm Deep by 80 mm high. It printed upto 72.6mm. But height at the other end is 70.4.Also the object came off the pad while printing as the nozzle and object got stuck! Any tips to avoid this??!!

If there's no problem doing that due to it being a replaceable part, do you think you could open up yours and tell us if their extruder-drive mechanism has any interesting features?

I ask because I expect companies selling work-out-of-the-box printers to try and make something that requires very little maintenance, in order to increase their customer base, and most of the maintenance I have ever performed on my reprap was on the extruder filament drive.

I've disassembled my extruder a couple of times in order to clean the drive gear. I had a heater line die in the ribbon cable which meant the drive gear stripped out trying to drive into a head that was too cold. The printer errors on 'head too cold' but obviously not fast enough to stop it stripping out. The fault was at the IDC connector at the extruder end so I cut back the cable and replaced it as a quick fix while pp3dp sent a new ribbon cable free of charge.

I think disassembling the extruder is actually part of the recommended maintenance in the manual?

Forrest: You say don't print big monolithic objects? You mean solid or just large? I've successfully printed quite chunky objects that needed to be structurally sound at the full bed size (130x130 although only up to about 100 high). I'm 100% convinced that having the printer inside a cardboard box at ~40-50 degrees is what allows this, although the acrylic spray can bed paint as well as having the bed level, a long pre-heat and a very 'squished' first raft layer helps.

The previous problem of the printed object dislodging from the platform is solved by leveling the platform. Basically the nozzle tip has to be at more or less uniform distance from all corners/center of the platform. This was done by adjusting the screws used for fixing the platform (very minor fine adjustment) Thanks to 3D printer Malaysia! After this calibration was done. Now its working fine!

Is there a US distributor for either of the Up! models? I'm looking into jumping into the 3D printing world and slowly settling on the Up! Mini (I really like the look of their software and ease, but I'm not sure if the far more expensive Up! Plus like you've got is worth the increase in price to me).

But... I was hoping maybe buying from someone a little more local could result in a bit of a shipping savings. I'm not having much luck, though. Does anyone know of a US source, or will I have to order from China to get one?